1. Field of the Invention
The invention relates to a circuit arrangement for a tuner, particularly a television tuner, for changing over several frequency ranges filtered out by bandpass filters, particularly the hyperband (160-430 mHz) and UHF band frequency ranges, by means of diodes which also serve as mixer diodes for IF mixing and which are connected to a common IF circuit.
2. Brief Description of the Prior Art
A circuit arrangement of this type is known from German Patent Specification No. 2927225. In this specification an IF oscillator and an IF mixer diode are associated with each frequency range. An IF circuit connected to an input of an IF amplifier is arranged behind each IF mixer diode. Consequently two inputs of an RF amplifier IC are required, for example, for the hyperband and the UHF band. The change-over between hyperband and UHF band is effected in that a circuit arrangement having a switching diode is arranged in each of the two frequency ranges which switching diode is switched with the aid of a direct voltage to be applied externally. In this manner a change-over between the frequency ranges can be effected.